News Release

BOTHELL, Wash. and INDIANAPOLIS, Ind., Dec 3, 2004 /PRNewswire-FirstCall via COMTEX/ -- Lilly ICOS's (NYSE: LLY; Nasdaq: ICOS) Cialis^® (tadalafil)(1), the only erectile dysfunction (ED) treatment clinically proven to both act fast and work up to 36 hours for most men, is marking its first year of availability in the United States.

Since its approval, Cialis has increased its share of total prescriptions every month in the U.S. For the week ended November 19, 2004, Cialis held a 21.7 percent share of new and 19.1 percent of total U.S. oral ED treatment prescriptions.(2) Cialis had a very strong initial launch and now continues to gain share against market leader Viagra^® (sildenafil citrate).

"It's been a tremendous first year for Cialis," said Matt Beebe, Cialis U.S. Brand Team Leader. "We started the year with a clear strategy: educate health care professionals and then men with ED about the benefits of Cialis and how it can help them. Do that, and many men will choose Cialis as their ED treatment. We've said all along that because Cialis gives a man and his partner up to 36 hours to choose the moment for intimacy that is right for them, it will be very successful in the ED marketplace."

Memorable Moments

Cialis was approved in the U.S. on November 21, 2003. The first year of Cialis in the U.S. has included several memorable milestones:

• November 11, 2003 Cialis named one of TIME Magazine's "Coolest Inventions"
• January 5, 2004 Cialis debuted as a PGA Tour sponsor at the Mercedes Championships in Maui, Hawaii
• February 1, 2004 Cialis television advertising campaign kicked-off during Super Bowl XXXVIII * February 27, 2004 Cialis surpassed Levitra in new prescriptions, though Cialis launched several months later
• May 18, 2004 Lilly ICOS announced title sponsorship of Cialis Western Open
• July 12, 2004 The Cialis Promise program launched with national advertising
• September 27, 2004 Cialis awarded "2004 Best Launch of the Year" by the Pharmaceutical Marketing Congress
• November 10, 2004 Cialis awarded "New Brand of the Year" by DTC Perspectives Magazine

The Cialis Promise Program

Lilly ICOS broke more new ground in 2004 by launching "The Cialis Promise," a program that is a first-of-its-kind among ED treatments. The Cialis Promise offers a free trial of Cialis to men with ED who have never used Cialis. If they like Cialis, Lilly ICOS will pay for another free Cialis sample. If they don't, Lilly ICOS will pay for a sample of the prescription ED tablet of their choice. In the first nineteen weeks of the Cialis Promise program, a vast majority of men who completed the program and requested a second free sample voucher chose Cialis. Full program details are provided at www.cialis.com .

A Promising Future

Cialis continues its market share growth in the U.S. and worldwide. In September 2004 in France and Australia, Cialis had a 38 percent share of the ED market. In many other countries where Cialis has been approved, it continues steady growth against Viagra.

"More than three million men around the world have tried Cialis. Men tell us they want an ED treatment that offers a long window of effectiveness," said Leonard Blum, ICOS Vice President, Sales and Marketing. "In addition to Cialis working for up to 36 hours, it also works fast. These benefits offer couples spontaneity and allow intimacy to happen when the moment is right for them, without feeling pressure to perform in a short amount of time."

About ED

ED is defined as the consistent inability to attain and maintain an erection sufficient for sexual intercourse. As of 2004, it is estimated that approximately 189 million men worldwide will report having ED.(3) Experts believe that 80 - 90 percent of ED cases are related to a physical or medical condition, like diabetes, cardiovascular diseases, and prostate cancer treatment, while 10 - 20 percent are due to psychological causes.(4,5) In many cases, however, both psychological and physical factors contribute to the condition.(6)

About Cialis

Cialis, approved by the FDA in November 2003 for the treatment of erectile dysfunction, is the only oral ED treatment shown to improve erectile function up to 36 hours in most men. Cialis can be taken without regard to food. The absorption of Cialis is not reduced by food, including high-fat foods. Cialis is currently available in approximately 100 countries, including Australia, Brazil, Mexico, Canada, the United States and countries throughout Europe. More than three million patients worldwide have been treated with Cialis since its first introduction in February 2003.

Cialis is available by prescription only and is not for everyone. Men taking nitrates, often used for chest pain, or certain alpha-blockers for prostate problems or high blood pressure, should not take Cialis. Such combinations could cause a sudden, unsafe drop in blood pressure.

Men should discuss their health status with their doctors to ensure Cialis is right for them and that they are healthy enough for sexual activity.

The most common side effects with Cialis were headache, upset stomach, delayed backache or muscle ache. Although rare, men who experience an erection for more than four hours should seek immediate medical attention. Men should not drink alcohol in excess with Cialis. Cialis does not protect a man or his partner from sexually transmitted diseases, including HIV.

Individual results may vary. Cialis studies were not designed to assess multiple intercourse attempts after a single dose.

For full patient information, visit www.cialis.com.

About Lilly ICOS LLC

Lilly ICOS LLC, a joint venture between ICOS Corporation (Nasdaq: ICOS) and Eli Lilly and Company (NYSE: LLY), developed tadalafil for the treatment of erectile dysfunction.

Lilly, a leading innovation-driven corporation is developing a growing portfolio of first-in-class and best-in-class pharmaceutical products by applying the latest research from its own worldwide laboratories and from collaborations with eminent scientific organizations. Headquartered in Indianapolis, Ind., Lilly provides answers -- through medicines and information -- for some of the world's most urgent medical needs. Additional information about Lilly is available at www.lilly.com . P-LLY

ICOS Corporation, a biotechnology company headquartered in Bothell, Washington, is dedicated to bringing innovative therapeutics to patients. ICOS is marketing its first product, Cialis (tadalafil), through Lilly ICOS LLC. ICOS is working to develop treatments for serious unmet medical conditions such as chronic obstructive pulmonary disease, benign prostatic hyperplasia, cancer and inflammatory diseases.

Except for historical information contained herein, this press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements are based on current expectations, estimates and projections about the industry, management beliefs and certain assumptions made by the management of ICOS and Lilly. Investors are cautioned that matters subject to forward-looking statements involve risks and uncertainties, including economic, competitive, governmental, technological, legal and other factors discussed in the two companies' respective filings with the Securities and Exchange Commission, which may affect the business and prospects of the two companies and Lilly ICOS. Results and the timing and outcome of events may differ materially from those expressed or implied by the forward-looking statements in this press release. More specifically, there can be no assurance that Cialis will achieve commercial success or that competing products will not pre-empt market opportunities that might exist for the product.

(1) Cialis^® is a registered trademark of Lilly ICOS LLC. All other trademarks are the property of their respective owners.

(2) IMS National Prescription Audit Plus7^™, November 2004.

(3) Data were extrapolated from Feldman HA, Goldstein I, Hatzichristou DG, Krane RJ. Impotence and its Medical and Psychosocial Correlates: Results of the Massachusetts Male Aging Study, Journal of Urology. Vol. 151, 54-61, January 1994 and World Population Projection Program Of United Nations (2002 Revision) with indirect standardization.

(4) Shabsigh, R. (2002). Back To Great Sex: Overcome ED and Reclaim Lost Intimacy. New York: Kensington.

(5) Diseases and Conditions: Impotence, http://www.impotence.org/FAQ/index.asp . Data accessed 11.20.03

(6) Lue, Tom F. Erectile Dysfunction. N Engl J Med 2000; 342: 1802-1813.